Figure 2.

Bioelectronics and multimodal biosensing with MXenes. (a) Schematics of an intracortical array patterned with 25 µm Ti₃C₂T_x and adjacent Au contacts for recording neural activity in vivo. The close-up view shows a scanning electron microscopy image of the surface of one Ti₃C₂T_x contact. The arrays can record in vivo intracortical neural activity with higher signal-to-noise ratio and reduced susceptibility to 60 Hz interference than Au (reproduced with permission from Reference 21). (b) Photograph of Ti₃C₂T_x-infused electrode arrays for electroencephalography (EEG). (c) MXene EEG electrode array placed on human forehead and imaged in 3T clinical MRI scanner using T1-weighted magnetization prepared rapid acquisition gradient echo. (b, c) Reproduced with permission from Reference 23. (d) Schematics of the photothermal stimulation of a dorsal root ganglion (DRG) neuron network with Ti₃C₂T_x flakes (reproduced with permission from Reference 30). (e) Schematics illustrating the operation of ssDNA/Ti₃C₂T_x sensors for the detection of SARS-CoV-2 nucleocapsid (N) gene (reproduced with permission from Reference 39). (f) Schematic illustrating DNA translocation through a MXene nanopore sensor (reproduced with permission from Reference 44). (g) Photoluminescent Ti₃C₂T_x MXene quantum dots (MQDs) for multicolor cellular imaging. UV–vis spectra (solid line), photoluminescence excitation (PLE) (dashed line), and photoluminescence (PL) spectra (solid line, Ex = 320 nm) of MQD-100 in aqueous solutions. (h) Merged bright-field and confocal images (Ex = 488 nm) of MQD-100 interfaced with RAW 264.7 cells. (g, h) Reproduced with permission from Reference 48.